[PATCH 4.19 031/110] selinux: Add __GFP_NOWARN to allocation at str_read()

From: Greg Kroah-Hartman
Date: Thu Nov 29 2018 - 09:29:26 EST


4.19-stable review patch. If anyone has any objections, please let me know.

------------------

From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>

commit 4458bba09788e70e8fb39ad003f087cd9dfbd6ac upstream.

syzbot is hitting warning at str_read() [1] because len parameter can
become larger than KMALLOC_MAX_SIZE. We don't need to emit warning for
this case.

[1] https://syzkaller.appspot.com/bug?id=7f2f5aad79ea8663c296a2eedb81978401a908f0

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+ac488b9811036cea7ea0@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
security/selinux/ss/policydb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1101,7 +1101,7 @@ static int str_read(char **strp, gfp_t f
if ((len == 0) || (len == (u32)-1))
return -EINVAL;

- str = kmalloc(len + 1, flags);
+ str = kmalloc(len + 1, flags | __GFP_NOWARN);
if (!str)
return -ENOMEM;